if you targtet shoot every weekend like I do ,and am totally obsessed with what a 17 can do downrange, then the mach 2. If you wanna zero at 100 yards, and be able to hit a pdog with a dead on hold out to 150 yards, or if you wanna just absolutely blow small game up, then the 17hmr.
Also with the mach2 , you can shoot 17 aggies or pmc through them.
If you think you may come across coyote while hunting, then the 17hmr.
if you are not going to target shoot with it past 150 yards, then the m2.
you wanna try for 200 yard targets on a calm day? the hmr.

358, you are different, absolutely special (Ed)!
I'm toying with the mach II, in a single shot, and, having a bunch of time in little CF .17's, know the drill. Barrels are the issue, and few barrel makers will tool for the caliber, more the pity, because a good one is a worshipful thing; I have pestered Bartlein barrels for a couple of tubes, in the caliber, for a couple of years; everything they do is computer managed, and cut rifled, which IMHO is the way things oughta be!
To the point of the thread, I think the HMR is over rated, and the Mach II is caught in the shadow.
At the point in time where Remington 'legitimised' the caliber, with the .17 Rem , I had several .17 Acklley Hornets, and Bee's, making meat daily, with lots less powder, and noise.
I think their effort was too much, then and now, as barrels are not cheap, and hold the same stance, with the newer rimfire rounds: all things, in moderation.

Gary, welcome to TFF!
Lad, I like the way you think! You mirror my thoughts, in many ways; never had a .22 Magnum, because .22 LR ammo was more accurate, even out beyond 100, if the rifle was 'right' and there are far more rifles, in the smaller case, that are!
Ditto, my feelings on the .17 cal rimfires; Start with an accurate platform, rebarrel, we're done!
Now, if I absolutely needed more power, and equivalent, or better, accuracy, there are the (Kinda Pricy) Cooper CCM calibers, or the simple 'Ackley Improved' .22 /.17 Hornet Calibers, which will more than double the RF Magnum range and power, for the same price in ammo,if you reload, as case attrition is a 'non factor' in these calibers, except at 'Max' loads.
Waiting on a barrel, right now, for a Stevens 44 1/2, presently in .22 LR, that shoots under a dime, at 100 yds, (actually, 2 barrels, one will be chambered in the Mach II, the other in .17 Ackley Hornet, as I also have a centerfire breechblock, fitted to the action), but this a 'proven' rifle, having 'had it's way' with a lot of, according to 'conventional wisdom', far more accurate bolt guns, from Anschutz, Remington, and Winchester!
The Shilen barrel, presently in this rifle, has shot consistantly in the threes, often in the twos, off a rest, in any weather.
Now, we all know, according to 'conventional wisdom' a 'take down, single shot' rifle, cannot do these things, so if it would not, I suppose I would fall back in line, but have yet to do so, because it continues to perform.
I will allow, this was not a 'cheap' rifle, then, or now; I bought it for the action, replaced, or re-created, most every thing else, in better material, and far closer tolerance, than the original; part of the game!
But, with experience in both calibers (.22 Ackley Hornet, and .17 Ackley Hornet) you cannot compare them to any rimfire; If you are gomma 'move up', then, get what you paid for; these are among the finest on the planet!

I think it boils down to money, usally does.I have a bit of all the guns in question., I would pick the 22 Hornet over all of them.You have enough gun for all small animals , can obtain wonderfull acuracy.once your set up cost is not that bad in reloading.
Bill